Reimplementing the bulk of std.meta iteratively

[Bruce Carneal]

On Sunday, 27 September 2020 at 16:32:18 UTC, claptrap wrote:
> On Sunday, 27 September 2020 at 03:46:52 UTC, Bruce Carneal 
> wrote:
>> On Sunday, 27 September 2020 at 02:31:36 UTC, Andrei 
>> Alexandrescu wrote:
>>>
>>
>> We're in an early stage of exploration of discovered 
>> capability, so I understand the excitement.  The C++ guys must 
>> have been way excited about their meta programming discoveries 
>> as well.
>>
>> Just a respectful reminder here: a discovered way to do 
>> something is not a designed way to do something.  Cleverness 
>> can take you a very very long way (Modern C++ anyone? :-) ) 
>> but it's unlikely that it will take you to appropriate 
>> simplicity.
>
> D: "Look ma I can peel an apple with a tin opener!"
>
> Mom(C++): "That's my boy... the band-aids are in the usual 
> place."

Andrei and others advanced us well beyond the mandated cleverness 
of C++ meta programming.  As Atila has put it, they helped make 
things "boring" through very good design.  I deeply admire that 
work.

I hope and believe that there is another such advance available 
to us in the form of type functions.  The recently discovered 
alternative, reify/dereify, appears to be equivalent in power but 
is, comparatively, baroque.

If the two approaches are actually equivalent in power, and in 
their ability to address the current template issues, then the 
baroque should be preferred if the language is closed to 
syntactic additions.

If the language is not closed, then choosing to displace the 
already prototyped type function capability with reify/dereify 
would represent a lost opportunity to administer another 
complexity smackdown.

Disclaimer: Andrei has stated, effectively, that I have little 
standing to opine on these issues.  It is true that while I use 
templates extensively I confine myself to very simple 
combinations thereof.  I am not experiencing the template pain 
reported by others.

Best wishes to those who continue to work in this area.  Here's 
hoping you lead us to a future that is extremely boring.